Abstract: To improve the positioning precision for short distance and to eliminate the calculation error caused by adopting the assumption of parallel incidence, the effects of approximate error on angle estimation and phase unwrapping ambiguity were analyzed. And the prerequisite for satisfying the approximation of parallel incidence was obtained. Furthermore, the method for the phase difference estimation of the actual incident angle and the relevant angle calculation was proposed, and the angle estimation precision could be improved. This angle detecting method with high precision by using phase interferometer is suitable for engineering applications with high requirement for precision, such as reciprocal positioning of multiple motion platforms, the rendezvous and docking for the spacecraft, short range object positioning on ground.

Key words: Actual incidence, Phase interferometer, Phase difference estimation, Rendezvous and docking